During February 2026, Liulan focused on backend development for the dataease/sqlbot repository, addressing a critical authentication issue affecting MCP route reliability. Using Python, Liulan identified that a missing trailing comma in whitelist.py led to implicit string concatenation, which inadvertently merged whitelist entries and blocked access to MCP endpoints through TokenMiddleware. By restoring the correct whitelist configuration, Liulan ensured that /mcp* routes were properly authenticated and accessible. The solution was implemented with minimal code changes, reducing risk and downtime, and was accompanied by clear documentation and commit messages, enhancing the maintainability and traceability of the backend authentication logic.